Forceps are used to place a variety of clips on the anatomy during surgery. A variety of clips usually hemostatic clips are applied with forceps. One type of hemostatic clip of particular interest is an aneurysm clip. One type of aneurysm clip is shown in U.S. Pat. No. 4,777,950.
Hemostatic clips, including aneurysm clips, are applied to blood vessels in various ways to close or strengthen a blood vessel during or after surgery. The jaws of a forceps are usually designed to receive a particular type of clip. A clip is loaded into the jaws by the surgical assistant and then handed to the surgeon who inserts the clip into the surgical site.
To load a clip into the jaws the surgical assistant opens the jaws and places the clip between the jaws manually and then closes the jaws enough to hold the clip in place so that it will not fall out during insertion. It is, however, important that the jaws not be closed too much so as to start to open the clip since that might interfere with the proper insertion of the clip.
One way of setting the jaws at a predetermined position is to use two projections from the inside of each handle of the forceps which overlap and interlock as is shown for example in U.S. Pat. No. 3,393,680. Although this is a satisfactory lock for some applications, it is not particularly well suited to applying an aneurysm clip. A leaf spring extending between the insides of the two opposing handles of the forceps is used to bias the handles apart so that when the lock is disengaged the forceps handles will open a predetermined amount thus opening the jaws of the corresponding predetermined amount.
Another kind of forceps locking mechanism is shown in U.S. Pat. No. 4,462,404. This forceps locking mechanism can be used to place the jaws at multiple positions. A leaf spring attached to the inside of one forceps handle extends across to the inside of the other forceps handle and engages a complex latch which is affixed to the inside of the opposing handle. Although this device works satisfactorily, it is complicated and has variety of parts which must be separately assembled to the forceps. Care must be taken with this kind of latch mechanism to make sure that it does not become damaged and misaligned during cleaning and sterilization of the forceps.
It would be useful to have a latching device of simpler design which could be used to set the jaws of the forcep in a variety predetermined spaced apart positions so that the surgical assistant could first load the clip into the jaws and then firmly set the clip into position without activating the clip. This would allow the surgical assistant to quickly load the clip and hand the instrument to the surgeon who could easily insert the clip into the surgical site. It would also be useful to have the latch recycled to its initial position as the surgeon releases his grasp on the forceps to further facilitate the loading of the next clip by the surgical assistant or repositioning or removal of a clip just placed without withdrawing the applier from the surgical site. Quick, one hand recycling of the latch mechanism would be very useful in repositioning or removing a clip.